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应我校地球科学与资源学院董海良教授和海洋学院关翔宇教授邀请，昆士兰大学Gordon Southam教授将来我校进行学术交流，并做学术报告。
题 目：Mineral Carbonation 时 间：2025年4月14日 下午15:00 地 点：逸夫楼612
摘 要：Carbonate cementation in surface and within endolithic habitats, e.g., stromatolites, intertidal low-latitude beachrock sediments and ultramafic mine waste, occurs via growth of biofilms that play a key role in weathering and in stabilizing and preserving these materials. While a range of chemical and biological factors influences carbonation, alkalinity generation by cyanobacteria activity is generally considered to be the primary driver in these contemporary geological systems. Though no single biogeochemical feature or process is responsible for carbonate precipitation in microbialites, recent work has highlighted the importance of microbialites in the consolidation / architecture of stromatolites well below the photic zone, but still within regions influence by tidal pumping, i.e., maintaining aerobic conditions. Cements in natural and synthesized beachrock, in a Shark Bay stromatolite and in kimberlite were characterised using X-ray fluorescence microscopy (XFM) and by using secondary electron and backscattered electron, scanning electron microscopy, suggesting that heterotrophic microbialite activity plays an important role in secondary, and perhaps tertiary, carbonate precipitation. In near surface environments, cyanobacteria (photosynthesis) creates alkaline microenvironments, which, when combined with high cation concentrations and inorganic carbon from heterotrophic activity, produces supersaturating conditions. 题 目：IODP Expedition 399 时 间：2025年4月16日 下午14:30 地 点：科研楼607
摘 要：Water rock interactions in surface to subsurface terrestrial and marine environments are critical to the biosphere. These systems produce energy, and release trace elements essential to life. In deep ultramafic marine systems, serpentinization is particularly important to the subsurface and ocean floor biome, producing hydrogen as well as small organic molecules that support life. International Ocean Discovery Program (IODP) Expedition 399 at the Atlantis Massif (30°N, Mid-Atlantic Ridge) provided an unprecedented opportunity to examine a 20-year-old, gabbroic borehole and weathered peridotite core. The gabbroic borehole (1309D), subjected to 20 years of bacteria-water-rock interactions, produced a friable weathered water-rock interface consisting of fossilized iron oxide biofilm intermixed with fine-grained iron-sulfide ‘mud’ on gabbro. Biofilm sampling was imprecise and occurred by scraping a 10 m long temperature-triggered water sampler down the ca. 1400 m, 1o from vertical borehole. While sample depths are unknown, the material must include some exposure to seawater oxygen over the past 20 years. Molecular, 16S rRNA gene sequencing indicated the presence of iron and sulfur cycling bacterial families such as Desulfobacteraceae, Desulfocapsaceae, Geopsychrobactereraceae, and Flavobacteriaceae. Oceanic drill core IODP-EXP399-1601A, which penetrated 60 m below the seafloor possessed an extensive weathering interval at ca. 30 m. Core recovery through this section was limited, consistent with the relatively soft, friable nature of weathered peridotite. Exposure to seawater and the subseafloor biosphere produced low bacterial abundances based on DNA extraction from weathered peridotite, consistent with unclassified Dehalococcoidia, Pseudomonadaceae, Rhodobacteraceae, Rhodanobacteraceae, Chitinophagaceae, Nitrosococcaceae, Desulfovibrionaceae, Microbacteraceae, Geodermatophilaceae, and Eubacteraceae bacterial families; possessing some unique bacterial lineages consistent with marine ecosystems. 报告人简介：Gordon教授是地质微生物学教授。他跨越生物和地质科学之间的传统界限，研究细菌对地壳物质的转化以及这些转化对地质时期的影响。研究区域从黄石国家公园到加拿大北极高纬度地区的阿克塞尔海伯格岛，南非的超深金矿（地表以下4公里），再到亚马逊盆地。在被任命为加拿大地质微生物学研究主席和加拿大西部大学环境与可持续发展主任之后，Gordon教授转到昆士兰大学并在那里领导了以下项目：（1）矿物碳酸化，利用产酸菌增强超镁铁性矿渣的风化，促进矿物碳酸化（CO2固存）；（2）通过加强铁的生物地球化学循环，促进含铁硬壳（canga）的形成，对铁矿场地进行生物修复；（3）生物浸出，侧重于干旱至热带生态系统中的低品位铜（澳大利亚和巴西）；（4）金矿勘探，研究细菌在催化砂金形成过程中所扮演的基本角色。 欢迎广大师生参加，研究生记学术报告一次！
地球科学与资源学院 海洋学院 极地地质与海洋矿产教育部重点实验室 国际合作与交流处
科技处 研究生院
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